A standard technique for medical diagnosis is to take a biopsy (a tissue sample), and have that biopsy analyzed by a laboratory. For example, taking a biopsy and testing the biopsy is often used to detect cancer.
The testing of biopsies for estrogen and progesterone receptors (ER and PR) has proven very useful in the detection and treatment of breast cancer. Specifically, the assessment of estrogen and progesterone receptors (ER and PR) status in breast cancer is widely used for the prediction of response to endocrine therapy and as a prognostic marker.
The immunohistochemistry (IHC) method is considered as a specific, sensitive, and economical method for the determination of estrogen and progesterone receptors status. The currently available ER and PR antibodies used for immunohistochemistry testing on formalin-fixed, paraffin-embedded tissues are either mouse monoclonal/polyclonal antibodies or rabbit polyclonal antibodies. The current antibody that has proven to be the best is the clone 1D5 mouse monoclonal antibody for ER and clone 1A6 mouse monoclonal antibody for PR.
Unfortunately, all the current ER and PR antibodies used for immunohistochemistry testing require a heat pretreatment for accurate results. This heat pretreatment is required for target retrieval. The heat pretreatment is a difficult and time-consuming step. Furthermore, the heat pretreatment may produce some problems, such as increasing staining background and inconsistency of the results. Therefore, it would be very desirable to have other testing systems that do not require this troublesome heat pre-treatment step.